Can coffee grounds be used to plant flowers

Coffee grounds can be used to grow flowers, but they need to undergo fermentation and maturation treatment. Untreated coffee grounds may damage plant roots due to strong acidity, nitrogen decomposition, and heat generation, but after decomposition, they can improve soil structure and provide nutrients.

Coffee grounds contain about 2% nitrogen and trace amounts of phosphorus and potassium, which are converted into slow-release organic fertilizers during the maturation process. Mix coffee grounds with garden soil in a ratio of 1:3 and ferment in a sealed container for 2-3 months, flipping once a week to promote aerobic decomposition. The fermented coffee grounds are dark brown and loose, with a pH value that increases from 4.5 to around 6.0, making them suitable for most flowers. Sour plants such as roses and hydrangeas can be directly mixed into the potting soil, with a dosage not exceeding 10% of the total substrate; It is recommended that neutral plants such as jackfruit and chlorophytum comosum be mixed with plant ash to neutralize acidity.

Direct use of fresh coffee grounds may cause mold growth or attract pests. Caffeine residue can inhibit the germination of some seeds, so it should be avoided for sowing flowers. Continuous use of coffee grounds requires monitoring of soil pH to prevent excessive acidification and iron manganese poisoning. Extreme acid loving plants such as azaleas and gardenia can use partially decomposed coffee grounds for a short period of time, but they need to be mixed with sulfur powder to adjust the acidity.

It is recommended to compost coffee grounds together with kitchen waste such as fallen leaves and eggshells, which can balance the carbon nitrogen ratio and reduce odors. Germination test can be conducted before use: Cultivate mung beans with processed coffee grounds, and a germination rate of over 70% indicates complete maturity. Potted flowers can be applied once a month, while ground plants should be applied before the rainy season to prevent nutrient loss. Pay attention to the condition of plant leaves. If yellowing or burnt edges occur, stop using immediately and rinse the soil.